Vegetation cutting apparatus

ABSTRACT

An apparatus for cutting vegetation wherein at least one line member protrudes exteriorly of the sidewall of a housing which is rotatable about a rotating axis. The line member is a tape and is wound upon a spool, which is mounted within the housing so that the width, which is greater than the thickness, is perpendicular to the plane of the spool. The flat tape line member is formed of a flexible band of material which extends exteriorly of the housing in a trailing position. Cutting means are incorporated to effect cut off of the line member during rotation of the housing and dispensing means are provided to extend additional line member a controlled increment of length during rotation of the housing. The cutting means is provided to cut off the excess end of the worn or broken line member. A clamping device clamps the line member to the housing when it is not rotating to prevent retraction of the line member into the housing.

BACKGROUND OF THE INVENTION

One field for this invention is directed to a weed and grass cuttingmachine which effects the cutting action by means of a length of aflexible band or bands, and more particularly to a portable power drivendevice which is capable of being readily moved by a person to achievethe cutting action.

In the past, there have been devices which employ a flexible line toachieve cutting weeds and grasses. These flexible line devices have beenknown to take the form of a power source attached to a shaft which, inturn, is connected to a whirling or rotating line holding head orhousing. Within the head or housing is at least one flexible cord thatextends exteriorly of the housing. The head or housing is rotated at aspeed sufficient to create line rigidity. The whirling cord is to beemployed to cut grass, weeds, and edge lawns. If the cord breaks, anadditional length of cord is unwound. Besides the advantage of suchdevices being useable in relatively inaccessible areas, such devicesalso have the advantage that if the cord comes into contact with theoperator's leg, hand or arm, the whirling cord would, at most, causeonly a small welt upon the operator's skin. Therefore, by using suchdevices, there is a significantly greater degree of safety than waspreviously possible with rigid steel blade types of cutting devices.

One disadvantage of the prior art type of cord cutting devices is thatthe cord has been known to be readily breakable. Once a cord was broken,it was necessary to stop the device, extract an additional length ofcord and cut the cords the equal length to retain satisfactory dynamicbalance prior to operating the device. It has not been uncommon to havemany cords break in a short time under heavy cutting conditions. Thismeans that there has been a significant amount of "down" time which ismost time consuming. This stop-start operation increases power sourcewear and energy usage.

There is a definite need for a line cutting apparatus in which the linemember is of a substantially superior strength to the line membersincorporated in prior line cutting apparatuses. In the event the linemember does break, a cutting device may be automatically activated tosever all line members and then appropriate line extending meansprovided to extend new portions of line members with each line memberbeing of equal length. This extending of the line member and the cuttingof the old line members is to be accomplished quickly and easily and ina matter of seconds without power shutdown. There is a further need forquick and easy replacement of the spool incorporated within the deviceupon which the line members are wound, preferably without the use ofhand tools.

SUMMARY OF THE INVENTION

The structure of this invention is directed to the construction of therotating or whirling head which is to be attached to a drive shaft whichis rotatably driven. The rotating or whirling head takes the form of ahousing within which is mounted a flexible line assembly mounted on aspool. The spool assembly has one or more line storage sections andwithin each spool section is wound one or more lengths of flexible linemember. Each of the line members extend through an opening in thehousing. The spool assembly may be quickly and easily removed andreplaced within the housing without the need of hand tools.

A cutting device is mounted in the path of the line to cut the flexibleline member. There is a separate cutter for each line member and thecutters are interconnected together through a ring and upon the ringcontacting a stationary surface during rotation of the device, the ringmember causes the cutters to be moved to cut the line members.

Also there is a line member clamping device which, when the head isbelow operational speed, the clamping device automatically binds eachline member to the housing to thereby prevent retraction of the linemember within the housing. When the rotation of the housing increases tooperational speed, each clamping member automatically releases itsrespective line member.

The line member is constructed of a specially formulated high strengthplastic material with the preferable type of material being anultra-high molecular weight polyolefin. The cross-sectionalconfiguration of the line member is to be such that the line member isgreater in width so that the line members will not be capable ofsignificantly bending toward the ground during use. This prevents awhipping action (that is common to round cross-sectional line) towardand away from the ground which is capable of causing "scalp" spotswithin a lawn area.

The device of this invention further includes dispensing means whichincludes an indexing sleeve which is capable of being activated while inmotion by external activating means. Upon the dispensing means beingactivated, the indexing sleeve permits the line assembly to be extendeda controlled amount with respect to the housing.

Thus, if one or more of the line members breaks or wears, the dispensingmeans causes segments of new line members to be extended from thehousing with each segment being of the same length.

One of the primary advantages of this invention is that the line memberemployed is significantly stronger than heretofore used and it isactually very difficult to break during operation.

A further advantage of this invention is that if the line member doesbreak or wear, the operator may dispense in a few seconds an equallength of line members to continue the cutting action, without stoppingthe operation of the device.

A further advantage of this invention is that each of the line membersare stronger in width to thereby control up and down action of the linemember which, in the past, has caused poor line control.

A still further advantage of this invention is that because of the widercutting face the line member is significantly less inclined to wrap or"bullwhip" around any fixed object which, in the past, has causedbreaking of the line member.

A still further advantage of this invention is that the line members canalso be replaced in just a matter of seconds without tools.

A still further advantage of this invention is that each line memberassumes a trailing position with respect to the rotational movement ofthe housing and this trailing position further makes it less likely thatthe line member will be broken. Outside the exit point, the line curvesto a radial position thus forming it's own shock absorber with thiscurve.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational side view of the whirling head or housingincorporated within a portable type of line cutting apparatus;

FIG. 2 is a cross-sectional view taken along line 2--2 of FIG. 1;

FIG. 3 is a cross-sectional bottom view taken along line 3--3 of FIG. 1;

FIG. 4 is a view similar to FIG. 2 but with the indexing means in theactivated position;

FIG. 5 is a view similar to FIG. 1 but with the cutting means in theactivated position;

FIG. 6 is a partial cross-sectional bottom view depicting the cuttingaction of a line member; and

FIG. 7 is an exploded isometric view of the internal components employedwithin the head or housing of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In FIG. 1, the apparatus 10 of the present invention includes arotatable housing 12, with line members 100 and 102 extending exteriorlyfrom the housing and adapted, upon rotation of the housing to effectcutting of vegetation. Cutting means are provided on a ring 122 withknife blades 148 and 150, attached, to cut off worn or broken linemembers 100 and 102 (FIGS. 3 and 6). If the operator touches ring 122 tothe ground, causing a reduction in the rotational speed of the ring 122,cutting blades 148 and 150 cut off lines 100 and 102 equally.

In FIG. 7, a dispensing means is shown including a program ring 112,having a key 114, which dispensing means can permit an unwindingrotation of spool 86 on which the line members 100 and 102 are mounted,to extend both line members an equal length. In FIG. 6 is shown clampingmeans (for line 100) including a leaf spring 154 and a clutch shoe 152secured thereto which prevents retraction of the line member. In FIGS. 3and 6, the line members 100 and 102 extend exteriorly from the housing12 in a trailing position, at an angle with respect to a radial line ofthe housing 12 to reduce sharp bends in the line members and reduce linebreakage at the exit point. The line members 100 and 102 have a widthdimension, which is, perpendicular to the plane of rotation, and whichis greater than the thickness dimension to provide greater rigidity,ease of unwinding, and better "nesting" of line in the container withoutsnags.

In FIG. 1 the apparatus 10 of this invention takes the form of anexterior housing 12 which has an annular side wall 14, closed at one endthereof by an end wall 16. A drive shaft 20 is to be rotatably driven bya motor (not shown). The drive shaft 20 operates through unit 22 torotate a mandril head 24. The mandril head 24 includes a member 26 whichis splined to the rotating shaft which is located within the unit 22.This keying is not shown.

In FIGS. 2 and 4, a bolt 28, is threadably secured also with the driveshaft located within the unit 22 and about the bolt 28 are located anadaptor plate 30 and a washer assembly 32. Upon tightening of the bolt28, the adaptor plate 30 is tightly secured and centered between thewasher assembly 32 and the rotating member 26. The adaptor plate 30 isdesigned to allow versatile attachment for many different kinds ofdriving mechanisms without major redesign. Therefore, upon rotation ofthe drive shaft 20, the entire mandril head 24 is rotated which includesthe bolt 28, the adaptor plate 30 and the washer assembly 32, as well asthe rotating member 26, thus rotating the complete head assembly.

In FIG. 2, an upper hub assembly 36 is attached by a plurality of bolts34 to the adaptor plate 30. The upper hub assembly 36 includes aninternal opening 38 which is to accommodate the bolt 28 and the washerassembly 32. Opening 38 is sufficiently large enough to accommodateknown drive shaft systems.

Fastened to the upper hub assembly 36 by means of a plurality of bolts40, is a lower hub assembly 42. The lower hub assembly 42 also includesan internal opening 44. Fixedly secured and centered between the upperhub assembly 36 and the lower hub assembly 42 is end plate 16 of thehousing 12.

In FIG. 2, the lower hub assembly 42 has integrally secured therewith acylindrical tubular section 46. Within the section 46 are located a pairof openings 48 and 50. The openings 48 and 50 are in fact, locatedfairly close to one another, however, this is not mandatory but there isa necessary spacing arrangement between the openings 48 and 50 relativeto posts 116 which will become apparent further on in the specification.Within opening 48 is located a steel ball 52. Openings 48 and 50 arestaked or restricted at their openings to retain the balls.

For illustrative purposes only, the steel balls 52 and 54 are located atwhat appears to be diametrically opposite each other within FIGS. 2 and4. However, in actual practice, these balls 52 and 54 cannot be locatedexactly diametrically opposite each other but they can be locatedsomewhat close to diametrically opposite each other. However, the balls52 and 54 in the actual embodiment are located as in FIG. 7 of thedrawings, "straddling" one post 116 of programming ring 112.

Slidably mounted within tubular section 46 is sleeve 62. At the top endof the sleeve 62 there is located a coil spring 64. The free end of thespring 64 contacts a plate 66 which is fixedly positioned by retainerring 68 within the lower hub assembly 42. When in the rest position, thespring 64 forces the sleeve 62 in an outward direction with respect tothe tubular section 46. This position is shown in FIG. 2 of thedrawings. In this position, the ball 52 is partially positioned withinthe annular recess 70 formed within the outer surface of the sleeve 62.The ball 54 is in abutting contact with the outer surface of the sleeve62, thus locking tubular section 46, programming ring 112 and spool 86together.

Located interiorly of the sleeve 62 is a longitudinal opening 72. Withinthe opening 72 is located a plunger 74. The plunger 74 within its outersurface thereof includes an annular recess 76. A ball 58 is mountedwithin an opening 56 formed within the sleeve 62. The ball 58 is capableof cooperating with the recess 76. However, when the ball 58 is notcooperating with the recess 76, the ball is in contact with the shoulder60 formed within the opening 44. In the normal at rest position, theplunger 74 is spring loaded in an outward position by means of spring 78which is located within cavity 80 formed within the sleeve 62. The innerend of the spring 78 rests against a shoulder of the inner end of thecavity 80 with the outer end of the spring 78 resting against a washer82 which is fixedly mounted upon the plunger 74. The outward movement ofthe plunger 74 with respect to the sleeve 62 is prevented by means ofretaining ring 84. With the plunger 74 in its normal at rest position,spring 78 is extended with the washer 82 resting against retaining ring84. In this position, the recess 76 does not connect with the ball 58and the ball 58 rests against a portion of the outside surface of theplunger 74 which causes the ball 58 to extend slightly and come againstshoulder 60 in opening 44. This prevents withdrawal movement or outwardmovement of the sleeve 62 from the tubular section 46 and attachingparts. This means that the spool assembly in the form of spool 86 isheld in position within the chamber 18. The spool 86 is held in thisposition by means of cuff 88. The cuff 88 is secured by ring 90 and theyrotate together. The rotating member 75 rotates on sleeve 62. The sleeve62 provides a bearing between snap rings 92 and 94. The cuff 88 isformed off a flexible material such as rubber or plastic. The springaction of the cuff 88 holds the spool 86 in position. Pressing ofplunger 74 allows replacement of the reel 86.

The spool 86 defines a first spool section 96 and a second spool section98. Within each of the spool sections 96 and 98 is wound one or morelengths of line, with line members 100 and 102 located within spoolsection 96 and spare line in section 98. As the line members 100 and 102are depleted the plunger 74 is pressed removing the sleeve 62 and thecuff 88 from the unit permitting removal of the spool 86 which may beturned over or replaced.

In FIG. 6, the line members 100 and 102 extend exteriorly from the sidewall 14 of the housing 12 180° apart from each other with the free endof the line member 100 conducted through opening 104 and the free end ofthe line member 102 conducted through opening 106. The line members 100and 102 extend exteriorly from the housing 12 at an angle with respectto a radial of the housing as shown in FIGS. 3 and 6. This type ofextension of the lines 100 and 102 allows the lines to come out of thehousing without sharp bends to reduce breakage of the lines. It alsoallows for heat removal without a very thick side wall in the housingfor a heat sink.

If, during use, one or more of the line members break, it is desirableto extend new and equal portions of line members exteriorly of the sidewall 14. To achieve this extension of the line members, a dispensingmeans is provided which will now be described.

In FIG. 7, the hub opening within the hub section of the spool 86 isdivided into a number of keyways 108. Each adjacent pair of recesses 108are separated by a raised section 110 on which posts 116 rest. A programring 112 is provided which has a key 114 formed thereon which can enterany one of keyways 108. Also extending from the lower edge of the ring112 are a number of spaced legs 116. There are eight in number of legs116 but any number could be used depending on the amount of line desiredto dispense. In actual practice, it is envisioned that the ring 112including the legs 116 will be fabricated integrally within the hubsection of the spool 86.

The program ring 112 is to be inserted within the opening within the hubof the spool 86 and the key 114 aligns with any one of the keyways 108.The program ring is held in place on tubular section 46 by retainingring 87. With the program ring 112 so installed, each leg 116 is locatedupon a raised section 110. Each of the legs 116 are pointed at theirinnermost end and since they are adapted to come into contact with balls52 and 54, the pointing of the legs is to avoid any possibility of theballs 52 and 54 "hanging up" directly upon a leg 116.

In FIG. 2, the sleeve 62 is in the downward position caused by theaction of spring 64 and the spring action of the cuff 88. The ball 54rests against a portion of the peripheral surface of the sleeve 62 whichcauses the ball 54 to partially extend between any two of the legs 116.The ball 52 cooperates with recess 70 which means that the ball 52 isnot in the circular path of any of the legs 116.

In FIG. 4, if the end of the sleeve 62 is brought into contact with afixed object by the machine operator the sleeve 62 is moved verticallyagainst the action of the spring 64 and the springing of the cuff 88 tothe position shown in FIG. 4 of the drawings. The cuff 88, being incontact with the spool 86, and connected to sleeve 62, is slowed down inspeed relative to housing speed causing a clutching or braking action onspool 86, legs 116 and ball 54 Thus all slack is taken up and balls 52and 54 are in a positive position for indexing (relative to legs 116).Then ball 54 retracts into the recess 70 which causes the ball 54 to betaken out of contact with one of the legs 116. At the same time, theball 52 in recess 70 has been forced outwardly between two of legs 116allowing ring 112 and spool 86 to rotate slightly which dispensesadditional lengths of line members 100 and 102.

The striking of the sleeve 62 upon the ground or other hard surface isonly for an instant and when it moves away from the ground, the sleeve62 then moves back to its position shown in FIG. 2. When such occurs,the ball 52 becomes reassociated with recess 70 and the ball 54 becomesassociated with the peripheral surface of the sleeve 62. The spool 86then pivots with respect to the housing 12 until the next leg 116contacts ball 54 whereupon the spool 86 is again fixed with respect tothe housing 12. The net result is that the spool 86 has rotated and willhave extended the line members 100 and 102. Each time the sleeve 62 isstruck, a new length of line member is caused to automatically extendfrom the housing 12. Although in the preferred embodiment the sleeve isshown moved upwardly to dispense additional line, it will beappreciated, from the teaching of the present invention, that thedispensing mechanism may be placed at a different part of the apparatusto enable a user to move a sleeve, shaft, pin, inclined plane or othersuitable member is dispense additional line.

The line members 100 and 102 are to be constructed of a very strongmaterial. In the past, these line members have been formed of circularcross-section and are of nylon. This type of material has been found toreadily break and also, the line members have a tendency to whiprelative to the ground as the device is being used. This type of actionis particularly undesirable because, at times, it is desirable to cutthe vegetation at a particular height. The result is that there aregouges or scalp areas formed on the vegetation which provides anunsightly appearance. Additionally, round line, under some conditions,will twist together above or below the housing forcing machine shutdown.

Each of the line members 100 and 102 of this invention is constructed inthe shape of a narrow flexible tape or band wherein the width of theband, which is greater than the thickness, is perpendicular to the planeof rotation of the housing 12. The result is that the band is most rigidin the width direction when rotating. Although the line member is shownhaving a rectangular cross section, the cross section may be anynon-circular shape provided the width dimension, which is perpendicularto the plane of rotation of the spool 86, is greater than the thicknessdimension.

The preferable type of material for each of the line members 100 and 102would be an ultra-high molecular weight polyolefin thermoplastic. Theproperties of this material are found to be that the material hasexcellent abrasion resistance, high-energy impact absorption, lowcoefficient of friction, a very low moisture absorption and is resistantto corrosion and chemicals. In use, the line members 100 and 102 areconstantly striking vegetation and also possibly fixed objects, such asrocks, brickwork, pipe, lamp poles, cement walk ways, and so forth. Withthis particular material, hardness actually is increased when impacted.Therefore, the material itself, when struck, has a tendency to becomestronger which is most desirable in the present application.

If one of the line members 100 or 102 comes into contact with a sharpobject or is repeatedly struck in the same spot against a hard object,the line member may break. This breaking of the line member preventsthat line member from cutting and also creates a dynamic imbalance ifthe other line member is not broken. Therefore, if a line member isbroken, it is desirable to cut all line members the same length prior tooperation of the dispensing means which releases the line members.

In FIGS. 3 and 6 is shown an outer ring 122 which when touched to theground at a slower than operational speed, there is a reduction of speedof the outer ring 122 with respect to the speed of the line memberscausing ring 122 to rotate cutting blades 148 and 150 to cut off lines100 and 102.

Fixedly mounted to the exterior surface of the side wall 14 and adjacentto (and on the trailing side) of the opening 106 is a guide means in theform of block 118 and opposing face 119. A similar such guide block 120and opposing face 121 is similarly located adjacent opening 104. Theguide means cause the line members to extend exteriorly of the housing12 at an angle with respect to a radial to, as indicated above, reducesharp bends and consequent breakage.

The surfaces of the guide blocks 118 and 120 and their respectiveassociated opposing faces 119 and 121 are formed of a suitable heatconductive material such as any suitable metal for providing a heatsink. During heavy cutting, the tape whips or vibrates and frictionalheat at the exit port is removed by the metal surfaces of the guideblocks 118 and 120 and opposing faces 119 and 121.

In FIG. 3, the annular ring 122 surrounds entirely the side-wall 14.Located within the ring 122 are a series of longitudinal slots, 124,126, 128, and 130. Each of the slots cooperate with separate pins, e.g.,pins 134 and 136. Also, there are secured to the housing side wall 14,diametrically opposite each other, support blocks 137 and 138 which havesecured thereto a pin 140 and 142, respectively, which, in turn,cooperate respectively with a slot formed within the ring 122 with theseslots being also similar to the slots 124 126, 128 and 130. A pair ofsprings 144 and 146 are interconnected between the ring 122 and thesidewall 14 of the housing 12. These springs function to exert acontinuous pull upon the ring 122 tending to place the ring 122 in theposition shown in FIG. 3 of the drawings with the cutting bladesretracted.

Guide block 120 provides support surface for the ring 122 which has aknife blade 148 mounted thereon adjacent the forward surface of theguide block 120. On the opposite side, a similar knife blade 150 ismounted upon the ring 122. With the housing 12 rotating, the operatoronly need to cause the ring 122 to come in contact with a fixed surface,such as the ground, piece of cement, or a wall which causes the ring 122to be momentarily stopped. Since the housing 12 continues to rotate, theknife blade 150 is quickly moved against the line member 102 andsimultaneously the knife blade 148 is moved against the line member 100.Once the ring 122 is then moved away from the fixed object, the springs144 and 146 return the cutters 148 and 150 to retract position spacedfrom the line members 100 and 102, respectively. In both instances, theline members 100 and 102 are severed adjacent guide blocks 118 and 120,and both are cut off equally. Alternatively, the knife blades may bearranged to act against anvil means or one blade can cut all livemembers. The cutting position of the cutters is shown in FIG. 6 of thedrawings.

This cutting of the line members is usually accomplished prior tooperating of the dispensing means which then is operated the desirednumber of times in order to extend the line members the desired distanceexteriorly of the housing 12.

Also located adjacent each of the openings 104 and 106 is a clampingmeans for each line member. When the device is at less than operatingspeed, it is desirable to prevent retraction of the line member towithin the spool 86 in chamber 18. To prevent this from happening, aclutch shoe 152 is located adjacent the opening 104 and is secured to aleaf spring 154. The leaf spring 154 is secured to a mounting block 156which, in turn, is fixedly secured to the side wall 14 of the housing12. When the device is in the at rest position (shown in FIG. 3), theleaf spring 154 forces the clutch shoe 152 in an inward direction towardthe side wall 14 and binds the line member 100 against the side wall 14.Once the device is at operating speed, the centrifugal force willovercome the force of the spring 154 and the clutch shoe 152 will bemoved outwardly and be spaced from the line member 100. This position isshown clearly in FIG. 6 of the drawings.

A similar clutch shoe 158, secured to a leaf spring 160 which is securedto a mounting block 162 in turn fixedly secured to the side wall 14, isemployed to connect with the line member 102.

The inner end of each of the line members 102 and 100 are fixed to thehub 160 of the spool 86 by being snapped under a small leaf spring 162which is fixedly secured to the hub 160.

Obviously minor modifications and variations are possible in the lightof the above teachings. It is therefore to be understood that theinvention can be practiced otherwise than as specifically described.

What is claimed is:
 1. A cutting apparatus comprising:a housingrotatable about an axis; a spool mounted within said housing having atleast one line member would therearound and extending therefromexteriorly of said housing for contacting and cutting vegetation byrapid circular movement exteriorly of said housing during rotation ofsaid housing; means connected to said housing for locking said spoolagainst rotation of said spool relative to said housing and forunlocking said spool during rotation of said housing to permit saidrelative rotation and unwinding of said line member from said spool; asupport ring mounted on said housing; and means secured to said supportring for cutting said line member when the speed of rotation of saidsupport ring decreases relative to the speed of rotation of said linemember.
 2. The apparatus as defined in claim 1 wherein said means forcutting comprises a cutting blade, and further including:a guide blockmounted between said spool and support ring for cutting said line memberthereagainst.
 3. The apparatus as defined in claim 2 wherein said guideblock includes a smoothly contoured metallic surface for contacting saidline member.
 4. A cutting apparatus comprising:a housing rotatable abouta center axis having an outer support ring mounted thereon; at least oneline member mounted within said housing having a portion extendingbeyond said outer support ring for rapid movement in a circular patternto contact vegetation and effect cutting thereof; and means secured tosaid support ring for cutting said line member when the speed ofrotation of said support ring decreases relative to the speed ofrotation of said line member.
 5. The apparatus as defined in claim 4wherein:said portion of said line member extends beyond said supportring at an angle with respect to a radial line from said center axis. 6.A cutting apparatus comprising:a housing rotatable about an axis; aspool mounted within said housing having at least one line member woundtherearound and extending therefrom exteriorly of said housing forcontacting and cutting vegetation by rapid circular movement exteriorlyof said housing during rotation of said housing; means connected to saidhousing for locking said spool against rotation of said spool relativeto said housing and for unlocking said spool during rotation of saidhousing to permit said relative rotation and unwinding of said linemember from said spool, said locking and unlocking means including:atleast one ball mounted in said housing, said ball having a lockingposition for locking said spool against said relative rotation and anunlocked position, and a sleeve movably mounted in said housing fordetermining by its position whether said ball is disposed in saidlocking or unlocked position.
 7. The apparatus as defined in claim 6wherein said means for locking and unlocking further includes means forreestablishing said locking after a segment of said line member has beenunwound.
 8. The apparatus as defined in claim 7 wherein saidreestablishing means automatically reestablishes said locking.
 9. Theapparatus as defined in claim 6 wherein said means for locking andunlocking further includes means for automatically returning said sleeveto a position for disposing said ball in said locking position followingmovement of said sleeve for disposing said ball in said unlockedposition.
 10. A cutting apparatus comprising:a housing rotatable aboutan axis; a spool mounted within said housing having at least one linemember wound therearound and extending therefrom exteriorly of saidhousing for contacting and cuttiing vegetation by rapid circularmovement exteriorly of said housing during rotation of said housing; andmeans connected to said housing for locking said spool against rotationof said spool relative to said housing and for unlocking said spoolduring rotation of said housing to permit said relative rotation andunwinding of said line member from said spool, said locking andunlocking means including:at least first and second balls mounted insaid housing, each of said balls having a locking position for lockingsaid spool against said relative rotation and an unlocked position, anda sleeve movably mounted in said housing for determining by its positionwhether each of said balls is disposed in said locking or unlockedposition.
 11. A cutting apparatus comprising:a housing rotatable aboutan axis; a spool mounted within said housing having at least one linemember wound therearound and extending therefrom exteriorly of saidhousing for contacting and cutting vegetation by rapid circular movementexteriorly of said housing during rotation of said housing; meansconnected to said housing for locking said spool against rotation ofsaid spool relative to said housing and for unlocking said spool duringrotation of said housing to permit said relative rotation and unwindingof said line member from said spool, said locking and unlocking meansincluding means for unlocking said spool in response to forceful contactof part of the apparatus with matter external to the apparatus; andmeans connected to said housing in contact with said spool forfrictionally resisting rotation of said spool in response to saidforceful contact, said resisting means including a flexible cuff.
 12. Ahousing and dispensing assembly for a cutting line member of a cuttingapparatus, comprising:a housing rotatable about an axis; a spool mountedwithin said housing for winding the line member therearound and forextending the line member therefrom exteriorly of said housing tocontact and cut vegetation by rapid circular movement exteriorly of saidhousing during rotation of said housing; and means connected to saidhousing for locking said spool against rotation of said spool relativeto said housing and for unlocking said spool during rotation of saidhousing to permit said relative rotation and unwinding of the linemember from said spool, said locking and unlocking means including:atleast one ball mounted in said housing, said ball having a lockingposition for locking said spool against said relative rotation and anunlocked position, and a sleeve movably mounted in said housing fordetermining by its position whether said ball is disposed in saidlocking or unlocked position.
 13. A housing and dispensing assembly fora cutting line member of a cutting apparatus comprising:a housingrotatable about an axis; a spool mounted within said housing for windingthe line member therearound and for extending the line member therefromexteriorly of said housing to contact and cut vegetation by rapidcircular movement exteriorly of said housing during rotation of saidhousing; and means connected to said housing for locking said spoolagainst rotation of said spool relative to said housing and forunlocking said spool during rotation of said housing to permit saidrelative rotation and unwinding of the line member from said spool, saidlocking and unlocking means including:at least first and second ballsmounted in said housing, each of said balls having a locking positionfor locking said spool against said relative rotation and an unlockedposition, and a sleeve movably mounted in said housing for determiningby its position whether each of said balls is disposed in said lockingor unlocked position.